This epidemiologic study will utilize observations on approximately 51,500 former students from Harvard and the University of Pennsylvania to identify psychosocial and other characteristics in youth predictive of site-specific and total cancers later in life. Physical examination and other college records of the years 1916-1950 comprise the initial data to be examined for associations with fatal and nonfatal cancers identified on death certificates or on self-assessed mail questionnaires during a 25-60 year followup period. To date, approximately 1,350 cancer deaths have occurred among these former students in approximately 1.85 million person-years of observation. The number of surviving (nonfatal) cancer patients has yet to be assessed. The study affords a prospective perspective for both hypothesis testing and hypothesis seeking. Analytic methods will include case-control univariate methods applied to the total population, and exposed-nonexposed multivariate methods applied to the entire University of Pennsylvania and portions of the Harvard population. Characteristics to be examined for their association with cancer represent psychological, social, demographic, physical, familial, and occupational factors. Site-specific cancers to be studied include lung, colorectal, pancreas, stomach, prostate, blood, lymphaden, and skin among men; and breast (and perhaps ovary, cervix, and endometrium) among women. Unlike cross-sectional and retrospective studies that would search for associations between psychosocial characteristics and cancer occurrence, the proposed study will utilize predocumented data on adolescents and young adults and thus avoid the need to infer previous from current behavior or to recall mood, thought, or behavioral characteristics antecedent to cancer diagnosis.